Cold spraying titanium-based corrosion-resistant coating with high interface bonding strength and preparation method of cold spraying titanium-based corrosion-resistant coating

Abstract

The invention belongs to the technical field of surface engineering and coatings, and particularly relates to a cold spraying titanium-based corrosion-resistant coating with high interface bonding strength and a preparation method of the cold spraying titanium-based corrosion-resistant coating with the high interface bonding strength. Firstly, an optical fiber laser and cold spraying equipment work synchronously, first-layer laser-assisted spraying is carried out, and titanium / steel micro-metallurgical bonding is achieved; and then the laser is turned off, surface layer spraying is completed through the in-situ forging effect of micro-forging powder, and the titanium-based corrosion-resistant coating with the high interface bonding strength is obtained. The interface bonding strength of the coating breaks through 100 MPa, the porosity is lower than 1%, the low-temperature solid forming advantage is achieved, titanium oxidation and matrix deformation are avoided, and the long-acting anti-corrosion requirement under the extreme environment of ocean engineering, energy equipment and the like is met.

Description

Technical Field

[0001] The invention belongs to the technical field of surface engineering and coating, and particularly relates to a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength and a preparation method thereof. Background Art

[0002] Iron-based materials are widely used in marine engineering, electric power, mechanical engineering and other fields due to their excellent properties such as high strength, cost-effectiveness, good machinability and reliability. However, key components of iron-based materials serving in extreme environments such as high salt / high humidity, large temperature differences, and strong radiation face accelerated corrosion and failure, resulting in a significant reduction in the stability, safety and life of engineering equipment. In industry, technologies such as covering layer protection (such as metal thermal spraying, heavy anti-corrosion coatings) and electrochemical protection (sacrificial anode protection method) are usually used, but these measures have the following problems in application: the construction of thermal spraying technology is difficult, the coating process is complex and the coating adhesion is low, the cathodic protection conditions are significantly limited, the cost is high, and there are environmental and health risks. In summary, there are still various problems with the existing corrosion protection methods for iron-based materials.

[0003] Compared to traditional structural materials, titanium and titanium alloys are lightweight, high-strength, have a strong tendency to self-passivate, and exhibit excellent corrosion resistance in various extreme environments. They have gained widespread recognition in heavy-corrosion applications such as marine engineering and the petrochemical industry. The high price of titanium and titanium alloy components limits their widespread adoption. However, titanium coating technology can retain the corrosion resistance of titanium within a primary material like steel, reducing titanium usage, extending the overall service life of equipment, and significantly reducing the cost of corrosion protection. Traditional liquid titanium coating preparation techniques primarily include laser cladding, plasma spraying, and supersonic flame spraying. Due to titanium's susceptibility to oxidation and inherent process characteristics, these techniques suffer from high component dilution, coating susceptibility to oxidation, high internal stresses that can lead to cracking and shedding, high coating costs, and low deposition and spraying efficiencies, limiting their widespread application. Cold spraying is a solid-state forming technique that utilizes high-speed impact and intense plastic deformation of micron-sized metal powder particles to effectively bond the particles to the substrate without melting. The process has attracted widespread attention due to its low operating temperature, no phase change and oxidation during the deposition process, little impact on the substrate, and high spraying and deposition efficiency. It has shown great potential in the preparation of oxygen-sensitive titanium-based coating materials.

[0004] The coating interface bonding strength and densification degree are key indicators for evaluating the service life of corrosion-resistant titanium-based coatings. Currently, the interface bonding strength of ordinary high-pressure cold-sprayed titanium-based coatings can only reach 10MPa to 50MPa. During service in extreme environments, the coating is prone to shedding, resulting in accelerated corrosion of the substrate (the coating interface bonding strength must reach above 100MPa). The degree of coating densification depends on the degree of plastic deformation of the cold-sprayed powder particles during the deposition process. The higher the degree of powder deformation, the easier it is to fill the micropores inside the coating, resulting in a higher coating density. However, the degree of deformation of cold-sprayed titanium-based powder is poor, resulting in a higher porosity in the coating.

[0005] Existing research shows that the main methods for improving the interfacial bonding strength of coatings include post-spraying heat treatment and laser-assisted spraying throughout the entire process. For substrates and coatings of different materials, post-spraying heat treatment of the coating will cause changes in the substrate structure, thereby affecting its own performance. For thin plate substrates, laser-assisted spraying can easily lead to high deformation of the substrate of precision parts and excessive residual stress in the coating due to heat input, which may lead to cracking and failure of the coating. The main methods for improving the degree of deformation of powder particles include increasing the powder particle speed to increase the kinetic energy of the powder during impact, increasing the powder temperature to improve the degree of powder softening, and introducing large-scale hard powder to assist forging. High-speed spraying is limited by the type of carrier gas used in the spraying process. Helium as an accelerating gas can significantly increase the speed of powder particles, but it is expensive and difficult to promote and apply. High-temperature spraying is limited by cold spraying equipment. Raising the carrier gas temperature can easily cause the spray gun to clog, seriously endangering the normal operation of the equipment. The introduction of large-scale hard powder can easily cause the coating to fall off or the hard powder to be embedded in the coating during the spraying process, thereby affecting the preparation and performance of titanium-based coatings.

[0006] Therefore, how to synergistically improve the coating interface bonding strength and densification degree is a key technical issue facing the full life service of titanium-based corrosion-resistant coatings. Summary of the Invention

[0007] The present invention aims to provide a cold-sprayed titanium-based corrosion-resistant coating with high interfacial bonding strength and a method for preparing the same. The preparation method utilizes a collaborative process of laser-assisted interface strengthening and micro-forging powder densification. First, a fiber laser and cold-spray equipment operate synchronously to perform a first layer of laser-assisted spraying, achieving a micro-metallurgical bond between titanium and steel. The laser is then turned off, and the in-situ forging effect of the micro-forging powder is utilized to complete the top layer spraying, resulting in a titanium-based corrosion-resistant coating with high interfacial bonding strength. The coating boasts an interfacial bonding strength exceeding 100 MPa and a porosity of less than 1%. This coating combines the advantages of low-temperature solid-state forming, avoiding titanium oxidation and substrate deformation, making it suitable for long-term corrosion protection in extreme environments such as marine engineering and energy equipment.

[0008] The first aspect of the present invention provides a preparation method of a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength, which comprises the following steps: using titanium-based powder as the first layer spraying raw material powder, adopting a laser-assisted cold spraying process, using a fiber laser and a cold spray gun to work synchronously, performing a first layer spraying on an iron-based material substrate, and forming a first layer of titanium-based coating through titanium / steel micro-metallurgical bonding; using a mixed powder of titanium-based powder and micro-forging powder as the surface layer spraying raw material powder, and using in-situ micro-forging assisted cold spraying to perform a surface layer spraying on the first layer of titanium-based coating to obtain a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength; wherein the hardness of the micro-forging powder is greater than or equal to the hardness of the titanium-based powder.

[0009] In some embodiments of the present invention, in the laser-assisted cold spraying, the carrier gas type of the cold spraying is nitrogen, the carrier gas temperature is 500° C. to 900° C., the carrier gas pressure is 3 MPa to 5 MPa, and the powder feeding rate is 20 g / min to 80 g / min.

[0010] In some embodiments of the present invention, in the in-situ micro-forging assisted cold spraying, the carrier gas type of the cold spraying is nitrogen, the carrier gas temperature is 500°C to 900°C, the carrier gas pressure is 3MPa to 5MPa, and the powder feeding rate is 20g / min to 80g / min.

[0011] In some embodiments of the present invention, in the in-situ micro-forging assisted cold spraying, the cold spray gun is installed on a robotic arm, the spraying distance is 20mm~40mm, the robotic arm movement speed is 50mm / s~400mm / s, the spacing between adjacent passes is 0.5mm~3mm, and the robotic arm movement trajectory is a "Z" scanning path.

[0012] In some embodiments of the present invention, in the laser-assisted cold spraying, the laser power of the fiber laser is 1 kW to 15 kW.

[0013] In some embodiments of the present invention, the cold spray powder spot sprayed by the cold spray gun overlaps with the laser spot emitted by the fiber laser and intersects on the surface of the iron-based material substrate.

[0014] In some embodiments of the present invention, in the laser-assisted cold spraying, the cold spray gun and the laser head of the fiber laser are integrated together on a robotic arm, and the cold spray gun and the laser head are arranged in the same vertical plane, with an angle between the two being 20° and 40°.

[0015] In some embodiments of the present invention, in the laser-assisted cold spraying, the spraying distance is 20 mm to 40 mm, the robot arm movement speed is 50 mm / s to 400 mm / s, the spacing between adjacent passes is 0.5 mm to 3 mm, and the robot arm movement trajectory is a "Z" scanning path.

[0016] In some embodiments of the present invention, the thickness of the first titanium-based coating layer is 50 μm to 150 μm.

[0017] In some embodiments of the present invention, the thickness of the cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength is 150 μm to 5000 μm.

[0018] In some embodiments of the present invention, the titanium-based powder includes at least one of titanium powder and titanium alloy powder.

[0019] In some embodiments of the present invention, the particle size of the titanium-based powder is 10 μm to 70 μm.

[0020] In some embodiments of the present invention, the mixing volume ratio of the titanium-based powder to the micro-forging powder is 1:1-5.

[0021] In some embodiments of the present invention, the micro-forging powder includes at least one of an iron-based powder, a titanium-based powder, and a nickel-based powder.

[0022] In some embodiments of the present invention, the particle size of the micro-forging powder is 200 μm to 500 μm.

[0023] In some embodiments of the present invention, the microhardness of the micro-forging powder is 300 HV to 600 HV.

[0024] In some embodiments of the present invention, the iron-based material matrix includes one of alloy steel and low carbon steel.

[0025] In some embodiments of the present invention, the preparation method further comprises: sandblasting the iron-based material substrate before performing the first layer spraying.

[0026] In some embodiments of the present invention, the titanium-based powder and the micro-forging powder are vacuum dried before cold spraying.

[0027] In some embodiments of the present invention, the surface roughness Ra of the iron-based material substrate after sandblasting is ≥ 3 μm.

[0028] In some embodiments of the present invention, the sandblasting process uses aluminum oxide powder with a particle size of 40 to 60 meshes; the sandblasting pressure is 0.6 MPa to 0.8 MPa.

[0029] In some embodiments of the present invention, the vacuum drying temperature is 40° C. to 80° C., and the drying time is 4 h to 12 h.

[0030] The second aspect of the present invention also provides a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength. The cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength is prepared using the preparation method described in the first aspect. The interface bonding strength of the cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength is ≥100MPa, and the porosity is ≤1%.

[0031] This invention integrates laser-assisted and in-situ micro-forging into cold spray technology. The initial laser-assisted layer significantly improves the coating's interfacial bonding strength without causing deformation or dimensional changes in the substrate. The in-situ micro-forging effect effectively reduces internal porosity defects in the coating, significantly improving coating quality. The synergistic effect of these two methods imparts excellent corrosion resistance to the substrate.

[0032] Through the collaborative innovation of "laser-assisted interface strengthening + micro-forging powder densification", the present invention overcomes the core problems of low interface bonding strength and high porosity of cold-sprayed titanium-based coatings: micro-metallurgical bonding is achieved at the interface between the titanium-based coating and the iron-based substrate, and the bonding strength exceeds 100MPa, avoiding the risk of coating shedding in extreme service environments; the plastic deformation kinetic energy generated by the high-speed impact of high-hardness micro-forging powder is used to perform in-situ forging and compacting of the titanium-based coating, reducing the porosity to below 1%, significantly improving the coating's resistance to penetration corrosion.

[0033] This method retains the advantages of cold spraying and low-temperature solid-state forming, significantly avoiding oxidation and phase transformation caused by melting titanium-based powders, thus maintaining titanium's inherent corrosion resistance. Furthermore, laser-assisted precise control promotes diffusion and bonding of the titanium powder and the substrate through localized thermal effects, while simultaneously controlling the substrate temperature below 300°C, thus preventing thermal deformation of the substrate material.

[0034] The present invention uses low-cost nitrogen as the accelerating gas, and has a higher powder feeding rate and spray gun moving speed, which significantly improves the deposition efficiency and spraying efficiency of coating preparation.

[0035] The cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength produced by the present invention has the characteristics of high performance, low cost and high efficiency, and provides a breakthrough solution for the long-life corrosion protection of engineering equipment with high corrosion resistance requirements such as marine engineering, petrochemical and energy equipment.

[0036] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 This is an SEM image of the cross section of the TA1 coating prepared in Example 1 of the present invention.

[0039] Figure 2 This is a morphology diagram of the diffusion layer between the TA1 coating and the substrate prepared in Example 1 of the present invention.

[0040] Figure 3 This is an SEM image of the cross section of the TC4 coating prepared in Example 2 of the present invention.

[0041] Figure 4 This is a morphology diagram of the diffusion layer between the TC4 coating and the substrate prepared in Example 2 of the present invention.

[0042] Figure 5 This is an SEM image of the cross section of the TC4 coating prepared in Comparative Example 1 of the present invention.

[0043] Figure 6 This is a morphology diagram of the interface between the TC4 coating and the substrate prepared in Comparative Example 1 of the present invention.

[0044] Figure 7 This is an SEM image of the cross section of the TC4 coating prepared in Comparative Example 2 of the present invention.

[0045] Figure 8 This is a morphology diagram of the diffusion layer between the TC4 coating and the substrate prepared in Comparative Example 2 of the present invention.

[0046] Figure 9 This is an SEM image of the cross section of the TA1 coating prepared in Comparative Example 3 of the present invention.

[0047] Figure 10 This is a morphology diagram of the diffusion layer between the TA1 coating and the substrate prepared in Comparative Example 3 of the present invention.

[0048] Figure 11 1 is the polarization curve of the TC4 coating and the Q235 steel substrate prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0049] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0050] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0051] In the description of the embodiments of the present invention, technical terms such as "first" and "second" are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance or to implicitly specify the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present invention, "plurality" means more than two, unless otherwise specifically defined.

[0052] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0053] In the description of the embodiments of the present invention, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exists simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0054] In the description of the embodiments of the present invention, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0055] In the description of the embodiments of the present invention, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on specific circumstances.

[0056] The first aspect of the present invention provides a method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interfacial bonding strength. The key to this method is the integration of laser-assisted and in-situ micro-forging into cold spray technology. The first layer of laser-assisted significantly improves the interfacial bonding strength of the coating without causing deformation or dimensional changes in the substrate. The in-situ micro-forging effect effectively reduces internal porosity defects in the coating, significantly improving the coating quality. The synergistic effect of these two methods imparts excellent corrosion resistance to the substrate.

[0057] The preparation method of the cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength in the present invention is specifically carried out according to the following steps.

[0058] Raw material preparation

[0059] In the embodiment of the present invention, titanium-based powder is used as the first layer of spraying raw material powder.

[0060] In an embodiment of the present invention, a mixture of titanium-based powder and micro-forging powder is used as the surface layer spraying raw material powder.

[0061] In some embodiments of the present invention, the volume ratio of the titanium-based powder to the micro-forging powder is 1:1 to 5. For example, the volume ratio of the titanium-based powder to the micro-forging powder can be one of 1:1, 1:2, 1:3, 1:4, 1:5, or any value within the above range.

[0062] In some embodiments of the present invention, the titanium-based powder includes at least one of titanium powder and titanium alloy powder. For example, titanium powder or titanium alloy powder can be used as the raw material powder for the first layer spraying, and a mixture of titanium powder and micro-forging powder or a mixture of titanium alloy powder and micro-forging powder can be used as the raw material powder for the surface layer spraying.

[0063] In some embodiments of the present invention, the titanium-based powder may be TA1, TA2, TC4 powder, etc.

[0064] In some embodiments of the present invention, the particle size of the titanium-based powder is 10 μm to 70 μm. The particle size of the titanium-based powder provided by the present invention can be a value between any two values within the above range, for example, it can be 10 μm to 20 μm, 10 μm to 40 μm, 20 μm to 60 μm, 30 μm to 70 μm. Exemplarily, the particle size of the titanium-based powder can be one of 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, or any value that meets the above range.

[0065] In some embodiments of the present invention, the micro-forging powder includes at least one of an iron-based powder, a titanium-based powder, and a nickel-based powder. For example, the micro-forging powder can be an iron-based powder, a titanium-based powder, a nickel-based powder, or the like.

[0066] In an embodiment of the present invention, the hardness of the micro-forging powder is greater than or equal to the hardness of the titanium-based powder. The microhardness of the titanium-based powder is 150HV to 400HV. For example, the microhardness of TA1 powder can be 150HV to 250HV, and the microhardness of TC4 powder is 300HV to 400HV.

[0067] In some embodiments of the present invention, the microhardness of the microforging powder is 300 HV to 600 HV. For example, the microhardness of the microforging powder can be one of 300 HV, 350 HV, 400 HV, 450 HV, 500 HV, 550 HV, 600 HV, or any value within the above range.

[0068] In some embodiments of the present invention, the particle size of the micro-forging powder is 200 μm to 500 μm. The particle size of the micro-forging powder provided by the present invention can be a value in the interval consisting of any two values within the above range, for example, it can be 350 μm to 500 μm, 300 μm to 400 μm, 350 μm to 450 μm. Exemplarily, the particle size of the micro-forging powder can be one of 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, or any value that meets the above range.

[0069] In some embodiments of the present invention, the micro-forging powder is stainless steel powder, and the stainless steel powder includes 1Cr13, 410, 441 stainless steel powder, etc.

[0070] In some embodiments of the present invention, the microhardness of the stainless steel powder is 350HV to 500HV. For example, the microhardness of the stainless steel powder can be 350HV, 400HV, 450HV, 500HV, or any value within the above range.

[0071] In some embodiments of the present invention, the particle size of the stainless steel powder is 200 μm to 500 μm. The particle size of the stainless steel powder provided by the present invention can be a range consisting of any two values within the above range, for example, 350 μm to 500 μm, 300 μm to 400 μm, or 350 μm to 450 μm. Exemplarily, the particle size of the stainless steel powder can be one of 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, or 500 μm, or any value that meets the above range.

[0072] In some embodiments of the present invention, before cold spraying, the titanium-based powder and the micro-forging powder are each independently subjected to a vacuum drying process to reduce moisture and increase powder fluidity, and then used as raw powders for cold spraying.

[0073] For example, the vacuum-dried titanium-based powder and the micro-forging powder are uniformly mixed in a volume ratio of 1:1 to 5, and the mixture is used as the raw material powder for the cold spraying surface layer spraying.

[0074] In some embodiments of the present invention, a vacuum drying oven is used for vacuum drying, and the vacuum drying temperature is 40°C to 80°C, and the drying time is 4 hours to 12 hours. For example, the vacuum drying temperature can be one of 40°C, 50°C, 60°C, 70°C, 80°C, or any value within the above range; the vacuum drying time can be one of 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, or any value within the above range.

[0075] In an embodiment of the present invention, the iron-based material matrix includes one of alloy steel and low-carbon steel, such as Q235 steel and Q345 steel.

[0076] In an embodiment of the present invention, the thickness of the iron-based material substrate is ≥3 mm, for example, it can be 3 mm, 4 mm, 5 mm, 7 mm, etc.

[0077] In some embodiments of the present invention, the iron-based material substrate is sandblasted before the first layer of spraying is performed, so that the surface roughness Ra of the iron-based material substrate is greater than or equal to 3 μm.

[0078] In some embodiments of the present invention, the sandblasting process uses aluminum oxide powder with a particle size of 40 to 60 mesh. For example, aluminum oxide powder with a particle size of 40 mesh, 45 mesh, 50 mesh, 55 mesh, 60 mesh, or any other particle size within the above range can be used.

[0079] In some embodiments of the present invention, the sandblasting pressure is 0.6 MPa to 0.8 MPa. For example, the sandblasting pressure can be one of 0.6 MPa, 0.7 MPa, 0.8 MPa, or any value within the above range.

[0080] In some embodiments of the present invention, the iron-based material substrate to be sprayed is degreased and rust-removed before sandblasting. For example, acetone can be used for degreasing and sandpaper can be used for rust removal.

[0081] Laser-assisted cold spray

[0082] In an embodiment of the present invention, a laser-assisted cold spraying process is adopted, in which a fiber laser and a cold spray gun work synchronously to perform a first layer of spraying on an iron-based material substrate, and a first layer of titanium-based coating is formed by titanium / steel micrometallurgical bonding.

[0083] In some embodiments of the present invention, the cold spray gun and the laser head of the fiber laser are integrated together on a robotic arm. The cold spray gun and the laser head are arranged on the same vertical plane. The angle between the cold spray gun and the laser head and the positions of the cold spray powder spot and the laser spot are adjusted, and the movement parameters of the robotic arm are set.

[0084] In some embodiments of the present invention, the angle between the cold spray gun and the laser head is 20° to 40°. For example, the angle between the cold spray gun and the laser head can be one of 20°, 30°, 40°, or any value within the above range.

[0085] In some embodiments of the present invention, the laser power of the fiber laser is 1 kW to 15 kW. For example, the laser power can be one of 1 kW, 2 kW, 3 kW, 4 kW, 5 kW, 6 kW, 7 kW, 8 kW, 9 kW, 10 kW, 11 kW, 12 kW, 13 kW, 14 kW, and 15 kW, or any value within the above range.

[0086] As some embodiments of the present invention, the cold spray powder spot sprayed by the cold spray gun overlaps with the laser spot emitted by the fiber laser, and the two work synchronously and intersect on the surface of the iron-based material substrate.

[0087] As some embodiments of the present invention, in laser-assisted cold spraying, the spraying distance is 20 mm to 40 mm, the robot arm movement speed is 50 mm / s to 400 mm / s, the spacing between adjacent passes is 0.5 mm to 3 mm, and the robot arm movement trajectory is a "Z" scanning path.

[0088] Exemplarily, the spraying distance can be one of 20mm, 30mm, 40mm or any value satisfying the above range value; the moving speed of the robotic arm can be one of 50mm / s, 60mm / s, 70mm / s, 80mm / s, 90mm / s, 100mm / s, 120mm / s, 150mm / s, 180mm / s, 200mm / s, 220mm / s, 250mm / s, 280mm / s, 300mm / s, 320mm / s, 350mm / s, 380mm / s, 400mm / s or any value satisfying the above range value; the spacing between adjacent passes can be one of 0.5mm, 0.1mm, 1.5mm, 2mm, 2.5mm, 3mm or any value satisfying the above range value.

[0089] In some embodiments of the present invention, the fiber laser is selected from a continuous fiber laser, and the laser power is set to a range of 1 kW to 15 kW. For example, the laser power can be one of 1 kW, 2 kW, 3 kW, 4 kW, 5 kW, 6 kW, 7 kW, 8 kW, 9 kW, 10 kW, 11 kW, 12 kW, 13 kW, 14 kW, and 15 kW, or any value within the above range.

[0090] In an embodiment of the present invention, the first layer spraying raw material powder is loaded into the first layer powder feeder, and the surface layer spraying raw material powder is loaded into the surface layer powder feeder, and the cold spraying related parameters of the cold spraying equipment are set, including carrier gas type, carrier gas temperature, carrier gas pressure and powder feeding rate.

[0091] As some embodiments of the present invention, the carrier gas type of cold spraying is nitrogen, the carrier gas temperature is 500° C. to 900° C., the carrier gas pressure is 3 MPa to 5 MPa, and the powder feeding rate is 20 g / min to 80 g / min.

[0092] In the present invention, the carrier gas temperature and pressure determine the impact velocity of the powder during the cold spraying process, and further determine the quality of the coating through the powder deformation ability. When the carrier gas temperature is <500°C and the carrier gas pressure is <3MPa, due to the low deposition rate of the powder, the impact kinetic energy of the titanium-based powder and the micro-forging powder is small, which is not enough to cause strong plastic deformation of the titanium-based powder, resulting in a large number of pore defects inside the coating; and when the carrier gas temperature is >900°C and the carrier gas pressure is >5MPa, on the one hand, the titanium-based powder may stick to the spray gun cavity due to excessive temperature, which may easily cause the risk of gun blockage. On the other hand, the current process parameters are the limit operating parameters of existing domestic cold spray equipment. The selection range of the powder feeding rate and the spray gun movement speed ensures that the thickness of the deposited single layer is maintained between 50μm and 150μm, which can give full play to the effect of the first layer laser assistance and the surface layer micro-forging.

[0093] The carrier gas temperature provided by the present invention can be one of 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C or any value within the above range.

[0094] The carrier gas pressure provided by the present invention can be one of 3 MPa, 4 MPa, 5 MPa or any value within the above range.

[0095] The powder feeding rate provided by the present invention can be one of 20g / min, 25g / min, 30g / min, 35g / min, 40g / min, 45g / min, 50g / min, 55g / min, 58g / min, 60g / min, 65g / min, 70g / min, 75g / min, 80g / min or any value that meets the above range.

[0096] In an embodiment of the present invention, the first layer powder feeder is turned on, the cold spraying equipment and the laser equipment are started, and the first layer of laser-assisted cold spraying is performed on the iron-based material substrate fixed on the workbench to complete the deposition of the first layer of titanium-based coating and obtain the first layer of titanium-based coating.

[0097] In some embodiments of the present invention, the thickness of the first titanium-based coating layer is 50 μm to 150 μm. For example, the thickness of the first titanium-based coating layer can be one of 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 125 μm, 130 μm, 140 μm, 150 μm, or any value within the above range.

[0098] In-situ micro-forging assisted cold spraying

[0099] In an embodiment of the present invention, in-situ micro-forging assisted cold spraying is used to perform surface spraying on the first titanium-based coating to produce a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength.

[0100] In some embodiments of the present invention, after the deposition of the first layer of titanium-based coating is completed, the first layer powder feeder is closed, the surface layer powder feeder is opened, and spraying is performed with only the cold spraying equipment turned on to obtain a titanium-based corrosion-resistant coating with high interface bonding strength.

[0101] In some embodiments of the present invention, in in-situ micro-forging assisted cold spraying, the carrier gas type of cold spraying is nitrogen, the carrier gas temperature is 500°C to 900°C, the carrier gas pressure is 3MPa to 5MPa, and the powder feeding rate is 20g / min to 80g / min.

[0102] The carrier gas temperature provided by the present invention can be one of 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C or any value within the above range.

[0103] The carrier gas pressure provided by the present invention can be one of 3 MPa, 4 MPa, 5 MPa or any value within the above range.

[0104] The powder feeding rate provided by the present invention can be one of 20g / min, 30g / min, 40g / min, 50g / min, 60g / min, 70g / min, 80g / min or any value that meets the above range.

[0105] In some embodiments of the present invention, in in-situ micro-forging assisted cold spraying, the spraying distance is 20 mm to 40 mm, the robot arm movement speed is 50 mm / s to 400 mm / s, the spacing between adjacent passes is 0.5 mm to 3 mm, and the robot arm movement trajectory is a "Z" scanning path.

[0106] Exemplarily, the spraying distance can be one of 20mm, 30mm, 40mm or any value satisfying the above range value; the moving speed of the robotic arm can be one of 50mm / s, 60mm / s, 70mm / s, 80mm / s, 90mm / s, 100mm / s, 120mm / s, 150mm / s, 180mm / s, 200mm / s, 220mm / s, 250mm / s, 280mm / s, 300mm / s, 320mm / s, 350mm / s, 380mm / s, 400mm / s or any value satisfying the above range value; the spacing between adjacent passes can be one of 0.5mm, 0.1mm, 1.5mm, 2mm, 2.5mm, 3mm or any value satisfying the above range value.

[0107] In some embodiments of the present invention, the overall thickness of the cold-sprayed high interface bonding strength titanium-based corrosion-resistant coating is 150 μm to 5000 μm. For example, the overall thickness of the titanium-based corrosion-resistant coating can be one of 150 μm, 200 μm, 300 μm, 360 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1200 μm, 1500 μm, 1800 μm, 2000 μm, 2200 μm, 2500 μm, 2800 μm, 3000 μm, 3200 μm, 3500 μm, 3800 μm, 4000 μm, 4200 μm, 4500 μm, 4800 μm, 5000 μm, or any value within the above range.

[0108] The second aspect of the present invention provides a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength. The key is that it is prepared using the preparation method described in the first aspect. The interface bonding strength of the cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength is ≥100MPa and the porosity is ≤1%.

[0109] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples, etc., can all be purchased on the market or can be obtained by existing methods; the amounts of the experimental reagents used, unless otherwise specified, are the amounts of reagents used in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods. It should be further noted that the following description is merely exemplary and does not specifically limit the present invention.

[0110] Example 1

[0111] A method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interfacial bonding strength comprises the following steps:

[0112] 1) TA1 powder with a particle size range of 10μm to 20μm and 441 stainless steel powder with a particle size range of 350μm to 500μm were vacuum dried separately at 80°C for 8 hours. After drying, a portion of the TA1 powder was used as the raw material powder for the first layer of cold spraying and loaded into the first layer powder feeder. The remaining portion of the TA1 powder was evenly mixed with the 441 stainless steel powder in a volume ratio of 1:3 and used as the raw material powder for the top layer of cold spraying and loaded into the top layer powder feeder.

[0113] 2) Q235 steel with a thickness of 5 mm was selected as the substrate. Before cold spraying, the substrate to be sprayed was degreased with acetone, then polished and rusted with 600-mesh, 1000-mesh, and 2000-mesh sandpaper, and then sandblasted. 40-60-mesh alumina powder was used for sandblasting, and the sandblasting pressure was 0.6 MPa-0.8 MPa. The surface roughness Ra of the substrate after sandblasting was 5.8 μm.

[0114] 3) Install the continuous fiber laser and cold spray gun on the robotic arm, adjust the angle between the cold spray gun and the laser head to 30°, and coincide the positions of the cold spray powder spot and the laser spot. Set the robotic arm parameters: spray distance is 30 mm, robotic arm movement speed is 350 mm / s, adjacent pass spacing is 2 mm, and the robotic arm movement trajectory is a "Z" scanning path.

[0115] 4) Set the cold spray-related parameters of the cold spray equipment: carrier gas type is nitrogen, carrier gas temperature is 500° C., carrier gas pressure is 4 MPa, and powder feeding rate is 40 g / min.

[0116] 5) First, the first layer of powder feeder was turned on, and the cold spray equipment and laser equipment were started. The first layer of laser-assisted cold spraying was performed on the Q235 steel substrate that had been sandblasted and fixed on the workbench. The laser power was 6 kW, and the first layer of TA1 coating was deposited. The thickness of the first layer of TA1 coating was 80 μm.

[0117] After the first layer of TA1 coating is deposited, the first layer powder feeder is closed and the surface layer powder feeder is opened. The surface layer spraying is carried out with only the cold spray equipment turned on. The robot arm setting parameters and cold spray related parameters are consistent with the parameters in the first layer laser assistance. Finally, a cold-sprayed TA1 corrosion-resistant coating with high interface bonding strength and a total thickness of 360μm is obtained.

[0118] Example 2

[0119] A method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interfacial bonding strength comprises the following steps:

[0120] 1) TC4 powder with a particle size range of 10μm to 40μm and 410 stainless steel powder with a particle size range of 300μm to 400μm were vacuum dried separately at 80°C for 6 hours. After drying, a portion of the TC4 powder was used as the raw material powder for the first layer of cold spraying and loaded into the first layer powder feeder. The remaining portion of the TC4 powder was evenly mixed with the 410 stainless steel powder in a volume ratio of 1:4 and used as the raw material powder for the surface layer of cold spraying and loaded into the surface layer powder feeder.

[0121] 2) Q345 steel with a thickness of 4 mm was selected as the substrate. Before cold spraying, the substrate to be sprayed was degreased with acetone, then polished and rusted with 600-mesh, 1000-mesh, and 2000-mesh sandpaper, and then sandblasted. 40-60-mesh alumina powder was used for sandblasting, and the sandblasting pressure was 0.6 MPa-0.8 MPa. The surface roughness Ra of the substrate after sandblasting was 6.2 μm.

[0122] 3) Install the continuous fiber laser and cold spray gun on the robotic arm, adjust the angle between the cold spray gun and the laser head to 30°, and coincide the positions of the cold spray powder spot and the laser spot. Set the robotic arm parameters: spray distance is 30 mm, robotic arm movement speed is 200 mm / s, adjacent pass spacing is 1 mm, and the robotic arm movement trajectory is a "Z" scanning path.

[0123] 4) Setting the cold spray-related parameters of the cold spray equipment: carrier gas type is nitrogen, carrier gas temperature is 750° C., carrier gas pressure is 4 MPa, and powder feeding rate is 45 g / min.

[0124] 5) First, the first layer of powder feeder was turned on, and the cold spray equipment and laser equipment were started. The first layer of laser-assisted cold spraying was performed on the Q345 steel substrate that had been sandblasted and fixed on the workbench. The laser power was 8 kW, and the first layer of TC4 coating was deposited. The thickness of the first layer of TC4 coating was 80 μm.

[0125] After the first layer of TC4 coating is deposited, the first layer powder feeder is closed and the surface layer powder feeder is opened. The surface layer spraying is carried out with only the cold spray equipment turned on. The robot arm setting parameters and cold spray related parameters are consistent with the parameters in the first layer laser assistance. Finally, a cold-sprayed TC4 corrosion-resistant coating with high interface bonding strength and a total thickness of 800μm is obtained.

[0126] Example 3

[0127] A method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interfacial bonding strength comprises the following steps:

[0128] 1) TC4 powder with a particle size range of 20μm to 60μm and 1Cr13 stainless steel powder with a particle size range of 350μm to 450μm were vacuum dried separately at 60°C for 8 hours. After drying, a portion of the TC4 powder was used as the raw material powder for the first layer of cold spraying and loaded into the first layer powder feeder. The remaining portion of the TC4 powder was evenly mixed with the 1Cr13 stainless steel powder in a volume ratio of 1:5 and used as the raw material powder for the surface layer of cold spraying and loaded into the surface layer powder feeder.

[0129] 2) Q235 steel with a thickness of 7 mm was selected as the substrate. Before cold spraying, the substrate to be sprayed was degreased with acetone, then polished and rusted with 600-mesh, 1000-mesh, and 2000-mesh sandpaper, and then sandblasted. 40-60-mesh alumina powder was used for sandblasting, and the sandblasting pressure was 0.6 MPa-0.8 MPa. The surface roughness Ra of the substrate after sandblasting was 6.0 μm.

[0130] 3) Install the continuous fiber laser and cold spray gun on the robotic arm, adjust the angle between the cold spray gun and the laser head to 30°, and coincide the positions of the cold spray powder spot and the laser spot. Set the robotic arm parameters: spray distance is 20 mm, robotic arm movement speed is 300 mm / s, adjacent pass spacing is 0.5 mm, and the robotic arm movement trajectory is a "Z" scanning path.

[0131] 4) Setting the cold spray-related parameters of the cold spray equipment: carrier gas type is nitrogen, carrier gas temperature is 800° C., carrier gas pressure is 5 MPa, and powder feeding rate is 75 g / min.

[0132] 5) First, the first layer of powder feeder was turned on, and the cold spray equipment and laser equipment were started. The first layer of laser-assisted cold spraying was performed on the Q235 steel substrate that had been sandblasted and fixed on the workbench. The laser power was 10 kW, and the first layer of TC4 coating was deposited. The thickness of the first layer of TC4 coating was 125 μm.

[0133] After the first layer of TC4 coating is deposited, the first layer powder feeder is closed and the surface layer powder feeder is opened. The surface layer spraying is carried out with only the cold spray equipment turned on. The robot arm setting parameters and cold spray related parameters are consistent with the parameters in the first layer laser assistance. Finally, a cold-sprayed TC4 corrosion-resistant coating with high interface bonding strength and a total thickness of 1200μm is obtained.

[0134] Example 4

[0135] A method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interfacial bonding strength comprises the following steps:

[0136] 1) Vacuum dry TA2 powder with a particle size range of 30μm to 70μm and 441 stainless steel powder with a particle size range of 300μm to 400μm at 60°C for 8 hours. After drying, a portion of the TC4 powder is used as the raw material powder for the first layer of cold spraying and is loaded into the first layer powder feeder. The remaining portion of the TA2 powder and the 441 stainless steel powder are evenly mixed in a volume ratio of 1:2 and used as the raw material powder for the top layer of cold spraying and loaded into the top layer powder feeder.

[0137] 2) Q345 steel with a thickness of 3 mm was selected as the substrate. Before cold spraying, the substrate to be sprayed was degreased with acetone, and then rusted by sandpaper of 600 mesh, 1000 mesh, and 2000 mesh, and then sandblasted. Alumina powder of 40 to 60 mesh was used for sandblasting, and the sandblasting pressure was 0.6 MPa to 0.8 MPa. The surface roughness Ra of the substrate after sandblasting was 6.5 μm.

[0138] 3) Install the continuous fiber laser and cold spray gun on the robotic arm, adjust the angle between the cold spray gun and the laser head to 30°, and coincide the positions of the cold spray powder spot and the laser spot. Set the robotic arm parameters: spray distance is 40 mm, robotic arm movement speed is 200 mm / s, adjacent pass spacing is 1 mm, and the robotic arm movement trajectory is a "Z" scanning path.

[0139] 4) Setting the cold spray-related parameters of the cold spray equipment: carrier gas type is nitrogen, carrier gas temperature is 700° C., carrier gas pressure is 4 MPa, and powder feeding rate is 58 g / min.

[0140] 5) First, the first layer of powder feeder was turned on, and the cold spray equipment and laser equipment were started. The first layer of laser-assisted cold spraying was performed on the Q345 steel substrate that had been sandblasted and fixed on the workbench. The laser power was 6 kW, and the first layer of TA2 coating was deposited. The thickness of the first layer of TA2 coating was 110 μm.

[0141] After the first layer of TA2 coating is deposited, the first layer powder feeder is closed and the surface layer powder feeder is opened. The surface layer spraying is carried out with only the cold spray equipment turned on. The robot arm setting parameters and cold spray related parameters are consistent with the parameters in the first layer laser assistance. Finally, a cold sprayed TA2 corrosion-resistant coating with high interface bonding strength and a total thickness of 2500μm is obtained.

[0142] Comparative Example 1

[0143] A method for preparing a cold-sprayed titanium-based corrosion-resistant coating comprises the following steps:

[0144] 1) TC4 powder with a particle size range of 10 μm to 40 μm was vacuum dried at a drying temperature of 80°C for 8 hours. The dried TC4 powder was loaded into the powder feeder of the cold spray equipment.

[0145] 2) Q235 steel with a thickness of 5 mm was selected as the substrate. The substrate to be sprayed was degreased with acetone, and then rusted by grinding with 600 mesh, 1000 mesh, and 2000 mesh sandpaper, and then sandblasted. Alumina powder of 40 to 60 mesh was used for sandblasting. The sandblasting pressure was 0.6 MPa to 0.8 MPa. The surface roughness Ra of the substrate after sandblasting was 4.2 μm.

[0146] 3) Install the cold spray gun on the robotic arm and set the robotic arm movement parameters: the spraying distance is 20 mm, the robotic arm movement speed is 200 mm / s, the interval between adjacent passes is 1 mm, and the robotic arm movement trajectory is a "Z" scanning path.

[0147] 4) The cold spray equipment was set with the following parameters: carrier gas type: nitrogen; carrier gas temperature: 850°C; carrier gas pressure: 5 MPa; and powder feed rate: 75 g / min. A TC4 coating with an average thickness of 750 μm was obtained after spraying.

[0148] Comparative Example 2

[0149] A method for preparing a cold-sprayed titanium-based corrosion-resistant coating comprises the following steps:

[0150] 1) TC4 powder with a particle size range of 10 μm to 40 μm was vacuum dried at a drying temperature of 60°C for 8 hours. The dried TC4 powder was loaded into the powder feeder of the cold spray equipment.

[0151] 2) Q345 steel with a thickness of 5 mm was selected as the substrate. The substrate to be sprayed was degreased with acetone, and then rusted by grinding with 600 mesh, 1000 mesh, and 2000 mesh sandpaper, and then sandblasted. Alumina powder of 40 to 60 mesh was used for sandblasting. The sandblasting pressure was 0.6 MPa to 0.8 MPa. The surface roughness Ra of the substrate after sandblasting was 6.3 μm.

[0152] 3) Install the cold spray gun on the robotic arm and set the robotic arm movement parameters: the spraying distance is 30 mm, the robotic arm movement speed is 250 mm / s, the interval between adjacent passes is 1 mm, and the robotic arm movement trajectory is a "Z" scanning path.

[0153] 4) The cold spray equipment was set with the following parameters: carrier gas: nitrogen, carrier gas temperature: 850°C, carrier gas pressure: 5 MPa, and powder feed rate: 60 g / min. A TC4 coating with an average thickness of 550 μm was obtained after spraying.

[0154] 5) The sprayed sample was placed in a heat treatment furnace for heat treatment. The heat treatment atmosphere was high-purity argon, the heat treatment temperature was 850°C, the heat treatment time was 2 hours, and the heating rate was 5°C / min. After the heat treatment was completed, the sample was cooled in the furnace to finally obtain the TC4 coating regulated by the post-spray heat treatment.

[0155] Comparative Example 3

[0156] A method for preparing a cold-sprayed titanium-based corrosion-resistant coating comprises the following steps:

[0157] 1) TA1 powder with a particle size range of 20 μm to 60 μm was vacuum dried at 80°C for 6 hours. The dried TA1 powder was loaded into the powder feeder of the cold spray equipment.

[0158] 2) Q235 steel with a thickness of 5 mm was selected as the substrate. The substrate to be sprayed was degreased with acetone, and then rusted by grinding with 600 mesh, 1000 mesh, and 2000 mesh sandpaper, and then sandblasted. Alumina powder of 40 to 60 mesh was used for sandblasting. The sandblasting pressure was 0.6 MPa to 0.8 MPa. The surface roughness Ra of the substrate after sandblasting was 6.2 μm.

[0159] 3) Install the continuous fiber laser and cold spray gun on the robotic arm, adjust the angle between the cold spray gun and the laser head to 30°, and coincide the positions of the cold spray powder spot and the laser spot. Set the robotic arm parameters: spray distance is 30 mm, robotic arm movement speed is 300 mm / s, adjacent pass spacing is 2 mm, and the robotic arm movement trajectory is a "Z" scanning path.

[0160] 4) Set the cold spray and laser parameters for the cold spray equipment: carrier gas type: nitrogen, carrier gas temperature: 800°C, carrier gas pressure: 4 MPa, powder feed rate: 50 g / min, and laser power: 3 kW. The laser and cold spray equipment operated synchronously, and after full laser-assisted spraying, a TA1 coating with an average thickness of 350 μm was obtained.

[0161] Performance Testing

[0162] 1. Coating interface bonding strength

[0163] The titanium-based corrosion-resistant coatings prepared in the examples and comparative examples were subjected to bonding strength tests according to the GBT 6396 2008 standard. The test results are shown in Table 1.

[0164] 2. Average porosity

[0165] The average porosity of the titanium-based corrosion-resistant coatings prepared in the examples and comparative examples was measured using Image J software. The test results are detailed in Table 1.

[0166] Table 1 Summary of the properties of titanium-based corrosion-resistant coatings in the examples and comparative examples

[0167] Group Coating interface bonding strength (MPa) Average porosity (%) Example 1 112 0.8 Example 2 127 0.6 Example 3 132 0.3 Example 4 122 0.7 Comparative Example 1 20 5.1 Comparative Example 2 126 2.9 Comparative Example 3 80 4.8

[0168] It can be seen from the data in Table 1 that the interface bonding strength of the coating obtained by the first layer laser-assisted combined with in-situ micro-forging-assisted cold spraying in the embodiment of the present invention is much higher than the interface bonding strength of the coating obtained by ordinary cold spraying in Comparative Example 1 and the full laser-assisted coating in Comparative Example 3, and is close to the interface bonding strength of the coating after heat treatment after spraying in Comparative Example 2, which can reach more than 110 MPa; the average porosity inside the coating in the embodiment of the present invention is <1%, the average porosity of the coating in Comparative Example 1 and Comparative Example 3 is relatively high, and in Comparative Example 2, although the coating porosity is improved, it is still relatively high.

[0169] 3. Metallographic sample preparation

[0170] In order to observe the cross-sectional morphology of the cold sprayed specimens, the specimen cross-sections were polished with 200 mesh, 400 mesh, 800 mesh, 1200 mesh, 1500 mesh, 2000 mesh, 3000 mesh, and 5000 mesh sandpaper, and further polished with silica suspension. The polished specimens were ultrasonically cleaned with alcohol and blown dry before SEM observation.

[0171] Metallographic specimens were prepared for the cross sections of the coatings in Examples 1 to 2 and Comparative Examples 1 to 3, and SEM observations were performed.

[0172] Figure 1 The microscopic morphology of the coating cross section prepared in Example 1 is shown in FIG. Figure 1 It can be seen from the figure that the coating is dense and has no defects.

[0173] Figure 2 The interface morphology between the coating and the substrate prepared in Example 1 shows that a continuous and dense diffusion layer is formed between the coating and the substrate.

[0174] Figure 3 The microscopic morphology of the coating cross section prepared in Example 2 is shown in FIG. Figure 3 It can be seen from the figure that the coating is dense and has no defects.

[0175] Figure 4 The interface morphology between the coating and the substrate prepared in Example 2 shows that a continuous and dense diffusion layer is formed between the coating and the substrate.

[0176] Figure 5 The microscopic morphology of a cross-section of the coating prepared in Comparative Example 1 reveals numerous pore defects within the coating. This is primarily due to insufficient powder deformation within the coating, resulting in pore defects and powder shedding caused by poor interparticle bonding. The overall porosity is characterized by high porosity away from the substrate. This is primarily due to the fact that the rear-end powder compacts the front-end powder during the spraying process, resulting in a lack of micro-forging of the surface powder from the rear-end powder, which results in a higher surface porosity.

[0177] Figure 6 The interface morphology between the substrate and the coating is shown in the cross section of the coating prepared in Comparative Example 1. It can be seen from the figure that crack defects appear at the interface position. The main form of interface bonding is mechanical meshing, with only a small amount of metallurgical bonding, which is the main reason for the poor interface bonding strength of the coating.

[0178] Figure 7 The microscopic morphology of a cross-section of the coating prepared in Comparative Example 2 shows that after heat treatment, some pores within the coating close due to grain boundary migration, but unclosed pore defects still exist. Furthermore, after heat treatment at 850°C, grain growth occurs within the coating and on the substrate, potentially leading to high-temperature failure of the substrate.

[0179] Figure 8 The interface morphology between the substrate and the coating of the cross section of the coating prepared in Comparative Example 2 shows that a continuous and dense diffusion layer is formed between the coating and the substrate, ensuring the metallurgical bonding between the coating and the substrate.

[0180] Figure 9To prepare the micromorphology of the coating cross section for comparative example 3, under full laser-assisted conditions, cold spraying process parameters higher than those of Example 1 were adopted, and the coating as a whole showed a uniform distribution of pores. On the one hand, due to the low impact velocity of the powder, the powder deformation ability was insufficient, resulting in unclosed pore defects. On the other hand, the power parameter setting of the full laser assistance should not be too high, which may easily lead to overall warping and deformation of the substrate. A lower power parameter setting leads to insufficient softening of the powder, and the appropriate power parameter setting is difficult to coordinate and control.

[0181] Figure 10 The interface morphology between the substrate and the coating of the coating cross section prepared in comparative example 3 shows that a certain diffusion layer is formed between the coating and the substrate. However, due to the low allowable laser power, the bonding method between the coating and the substrate is metallurgical bonding and mechanical meshing, and the coating interface bonding strength shows a lower value than that of the embodiment of the present invention.

[0182] In the comparative examples, conventional cold spraying, post-spraying heat treatment and full-process laser-assisted spraying all have difficulties in achieving a balance among the internal densification degree of the coating, high interface bonding strength of the coating and low damage to the substrate, and cannot guarantee the long service life of the titanium-based coating equipment. However, the first-layer laser-assisted bonding surface layer micro-forging technology in the embodiment of the present invention fully gives play to its advantages and can prepare a titanium-based corrosion-resistant coating with synergistically improved high density and high interface bonding strength.

[0183] 4. The titanium-based coating prepared in Example 3 was subjected to open circuit potential and potentiodynamic polarization tests on the Q235 substrate at a scan rate of 0.001 mV / s. The polarization curves of the two materials are shown in FIG. Figure 11 shown.

[0184] The curves of TC4 coating and Q235 substrate were fitted and analyzed to obtain the relevant experimental parameters of the coating in Example 3: the open circuit potential of TC4 coating was -0.17374 V, and the self-corrosion current density was 0.697 μA / cm 2 The self-corrosion potential is -0.485V, and the corrosion rate is 0.006mm / y. The open circuit potential of the Q235 substrate is -0.51745V, and the self-corrosion current density is 34.693μA / cm 2 The self-corrosion potential is -1.027V and the corrosion rate is 0.404mm / y.

[0185] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength, characterized in that: The following steps are involved: Titanium-based powder is used as the first layer of spraying raw powder. Laser-assisted cold spraying process is adopted. Fiber laser and cold spray gun work synchronously. The first layer of spraying is carried out on the iron-based material substrate. The first layer of titanium-based coating is formed through titanium / steel micro-metallurgical bonding. A mixed powder of titanium-based powder and micro-forging powder is used as the surface spraying raw material powder, and in-situ micro-forging assisted cold spraying is used to perform surface spraying on the first layer of titanium-based coating to obtain a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength; wherein the hardness of the micro-forging powder is greater than or equal to the hardness of the titanium-based powder.

2. The method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength according to claim 1, characterized in that: In the laser-assisted cold spraying, the carrier gas type of the cold spraying is nitrogen, the carrier gas temperature is 500° C. to 900° C., the carrier gas pressure is 3 MPa to 5 MPa, and the powder feeding rate is 20 g / min to 80 g / min.

3. The method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength according to claim 1, wherein: In the in-situ micro-forging assisted cold spraying, the carrier gas type of the cold spraying is nitrogen, the carrier gas temperature is 500° C. to 900° C., the carrier gas pressure is 3 MPa to 5 MPa, and the powder feeding rate is 20 g / min to 80 g / min; and / or, In the in-situ micro-forging assisted cold spraying, the cold spray gun is set on the robotic arm, the spraying distance is 20mm~40mm, the robotic arm movement speed is 50mm / s~400mm / s, the adjacent pass spacing is 0.5mm~3mm, and the robotic arm movement trajectory is a "Z" scanning path.

4. The method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength according to claim 1, wherein: In the laser-assisted cold spraying, the laser power of the fiber laser is 1 kW to 15 kW; and / or, The cold spray powder spot sprayed by the cold spray gun overlaps with the laser spot emitted by the fiber laser and intersects on the surface of the iron-based material matrix.

5. The method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength according to claim 1, wherein: In the laser-assisted cold spraying, the cold spray gun and the laser head of the fiber laser are integrated together on a robotic arm, and the cold spray gun and the laser head are arranged in the same vertical plane with an angle between them of 20° and 40°; and / or, In the laser-assisted cold spraying, the spraying distance is 20 mm to 40 mm, the robot arm movement speed is 50 mm / s to 400 mm / s, the spacing between adjacent passes is 0.5 mm to 3 mm, and the robot arm movement trajectory is a "Z" scanning path.

6. The method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength according to claim 1, wherein: The thickness of the first titanium-based coating is 50 μm to 150 μm; and / or, The thickness of the cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength is 150 μm to 5000 μm.

7. The method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength according to claim 1, wherein: The titanium-based powder includes at least one of titanium powder and titanium alloy powder; and / or, The particle size of the titanium-based powder is 10 μm to 70 μm.

8. The method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength according to claim 1, wherein: The mixing volume ratio of the titanium-based powder to the micro-forging powder is 1:1-5; and / or, the micro-forging powder includes at least one of an iron-based powder, a titanium-based powder, and a nickel-based powder; and / or, The particle size of the micro-forging powder is 200 μm to 500 μm; and / or the micro-hardness of the micro-forging powder is 300 HV to 600 HV; Preferably, the iron-based material matrix includes one of alloy steel and low carbon steel.

9. The method for preparing a cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength according to claim 1, wherein: The preparation method further comprises: sandblasting the iron-based material substrate before spraying the first layer; and / or, performing vacuum drying on the titanium-based powder and the micro-forging powder before cold spraying; Preferably, the surface roughness of the iron-based material substrate after sandblasting is Ra ≥ 3 μm; and / or, the sandblasting is performed using aluminum oxide powder with a particle size of 40 to 60 mesh; and the sandblasting pressure is 0.6 MPa to 0.8 MPa; Preferably, the vacuum drying temperature is 40° C. to 80° C., and the drying time is 4 h to 12 h.

10. A cold sprayed titanium-based corrosion-resistant coating with high interface bonding strength, characterized in that: The cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength is prepared by the preparation method according to any one of claims 1 to 9. The interface bonding strength of the cold-sprayed titanium-based corrosion-resistant coating with high interface bonding strength is ≥100 MPa, and the porosity is ≤1%.

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